The Book of Mormon claims that the
ancient American populations are descended from the Lamanites, who
originated from ancient Israel 2,600 years ago. Both the Nephites
and the Lamanites were white-skinned, until God put a curse of black skin
on them because of their unbelief. However, ancient American artwork
reveals no evidence for the “white, and exceedingly fair and delightsome”
Nephites, even though they were said to be prevalent in the Americas for
900 years.

http://www.godandscience.org/cults/sld029.html
Last Modified June 14, 2008